The score model (\(f\) ) in Eq. (REF ) was trained on 14,539 T2-weighted brain images from the fastMRI dataset [1]}. Sensitivity maps were estimated using ESPIRiT [2]}. Simulated ground truth motion states (\(\kappa _{GT}\) ) were chosen as \(\kappa _{\mathrm {GT}} \sim U(-2,2)\)  i.i.d. for each TR. This level was chosen based off the severity of the resulting artifacts which visually matched motion-corrupt data from prior work [3]} and led to nondiagnostic image quality even at low accelerations. The prior over motion parameters used in our score update steps was \(\kappa \sim U(-15,15)\)  so as not to assume perfect knowledge over the prior distribution which generated the motion parameters.
